<template>
  <canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
</template>
<script lang="ts" setup name="SIdentify">
import { onMounted, ref, toRefs, getCurrentInstance, watch } from 'vue'
const { proxy } = getCurrentInstance()
defineProps({
  identifyCode: {
    type: String,
    default: '1234',
  },
  fontSizeMin: {
    type: Number,
    default: 20,
  },
  fontSizeMax: {
    type: Number,
    default: 35,
  },
  backgroundColorMin: {
    type: Number,
    default: 180,
  },
  backgroundColorMax: {
    type: Number,
    default: 240,
  },
  colorMin: {
    type: Number,
    default: 50,
  },
  colorMax: {
    type: Number,
    default: 160,
  },
  lineColorMin: {
    type: Number,
    default: 40,
  },
  lineColorMax: {
    type: Number,
    default: 180,
  },
  dotColorMin: {
    type: Number,
    default: 0,
  },
  dotColorMax: {
    type: Number,
    default: 255,
  },
  contentWidth: {
    type: Number,
    default: 112,
  },
  contentHeight: {
    type: Number,
    default: 38,
  },
})
// 生成一个随机数
function randomNum(min: number, max: number) {
  return Math.floor(Math.random() * (max - min) + min)
}
// 生成一个随机的颜色
function randomColor(min: number, max: number) {
  let r = randomNum(min, max)
  let g = randomNum(min, max)
  let b = randomNum(min, max)
  return 'rgb(' + r + ',' + g + ',' + b + ')'
}
function drawPic() {
  let canvas = document.getElementById('s-canvas')
  let ctx = canvas.getContext('2d')
  ctx.textBaseline = 'bottom'
  // 绘制背景
  ctx.fillStyle = randomColor(
    proxy.backgroundColorMin,
    proxy.backgroundColorMax
  )
  ctx.fillRect(0, 0, proxy.contentWidth, proxy.contentHeight)
  // 绘制文字
  for (let i = 0; i < proxy.identifyCode.length; i++) {
    drawText(ctx, proxy.identifyCode[i], i)
  }
  drawLine(ctx)
  drawDot(ctx)
}
function drawText(ctx: any, txt: string, i: number) {
  ctx.fillStyle = randomColor(proxy.colorMin, proxy.colorMax)
  ctx.font = randomNum(proxy.fontSizeMin, proxy.fontSizeMax) + 'px SimHei'
  let x = (i + 1) * (proxy.contentWidth / (proxy.identifyCode.length + 1))
  let y = randomNum(proxy.fontSizeMax, proxy.contentHeight - 5)
  var deg = randomNum(-45, 45)
  // 修改坐标原点和旋转角度
  ctx.translate(x, y)
  ctx.rotate((deg * Math.PI) / 180)
  ctx.fillText(txt, 0, 0)
  // 恢复坐标原点和旋转角度
  ctx.rotate((-deg * Math.PI) / 180)
  ctx.translate(-x, -y)
}
function drawLine(ctx: any) {
  // 绘制干扰线
  for (let i = 0; i < 3; i++) {
    ctx.strokeStyle = randomColor(proxy.lineColorMin, proxy.lineColorMax)
    ctx.beginPath()
    ctx.moveTo(
      randomNum(0, proxy.contentWidth),
      randomNum(0, proxy.contentHeight)
    )
    ctx.lineTo(
      randomNum(0, proxy.contentWidth),
      randomNum(0, proxy.contentHeight)
    )
    ctx.stroke()
  }
}
function drawDot(ctx: any) {
  // 绘制干扰点
  for (let i = 0; i < 30; i++) {
    ctx.fillStyle = randomColor(0, 255)
    ctx.beginPath()
    ctx.arc(
      randomNum(0, proxy.contentWidth),
      randomNum(0, proxy.contentHeight),
      1,
      0,
      2 * Math.PI
    )
    ctx.fill()
  }
}
watch(
  () => proxy.identifyCode,
  (newValue: string, oldValue: string) => {
    drawPic()
  }
)
onMounted(() => {
  drawPic()
})
</script>
